A. the serial 1/1 address
B. the serial 2/0 address
C. a randomly generated internal address
D. the configured router - id address

A.Interfaces have a default metric of 1.
B.Level 1 is intra - area and level 2 is interarea.
C.Level 1 routing is between an end system (ES) and IS while Level 2 routing is between an IS and IS.
D. Hosts send ISHs while routers send ESHs.
E. IS - IS is an open standard.
F. Metrics depend on interface speed.